The copending application of L. Baranyai et. al. Ser. No. 391,698, filed June 24, 1982, now U.S. Pat. No. 4,481,624, discloses a time division multiplex conferencer for continuously summing and outputting digital message samples received from n subscribers in n respective time slots. Message samples collected from each subscriber of a conference connection are summed during a first time frame and outputted during a second time frame. Besides establishing one or more conference-type connections between two or more subscribers, the conferencer also has the ability to establish broadcast and monitor connections.
In the digital conferencer of the cited Baranyai et. al. case, "prefetching" techniques are used to reduce memory requirements to allow the circuit to be integrated into a single chip. This prefetching imposes a restriction, however, which prevents time slots at the frame boundaries from participating fully in the same conference. More specifically, the adjacent time slots (i.e., time slots 0 and 255) at the frame boundaries cannot participate fully in a given conference connection. Preferably, a conferencing system should not restrict or impose any dependency on time slot assignment, i.e., conferencing should be completely independent of time slot assignments within a given frame.